Because of the nature of a solar cell module, it is often the case that a solar cell module is installed outdoors. Therefore, in order to protect solar cell elements, electrodes, wires, and the like, for example, a transparent glass plate is disposed on a front side thereof and, for example, a laminated sheet of aluminum foil and a resin film, a laminated sheet of resin films, or the like is disposed on a back side thereof.
For example, proposed in Japanese Patent Application Laid-Open Publication No. 11-261085 (Patent Document 1) is a back side protective sheet for a solar cell, which includes a sheet of a polyethylene resin having a density greater than or equal to 0.94 g/cm3 and less than or equal to 0.97 g/cm3 and has weather resistance and a moisture-proof property.
In addition, for example, proposed in Japanese Patent Application Laid-Open Publication No. 2000-294813 (Patent Document 2) is a back cover material for a solar cell, comprising an outer film and a moisture-proof film which are laminated and integrated by using an ethylene-vinyl acetate copolymer adhesive, the moisture-proof film having a film whose base material surface has thereon a coating film formed of an inorganic oxide. Here, a fluorocarbon resin film such as a polyvinylidene fluoride film (PVDF) and a polyvinyl fluoride film (PVF) is used as the outer film, and a thickness of the outer film is 12 to 200 μm.
Patent Document 1: Japanese Patent Application Laid-Open Publication No. 11-261085
Patent Document 2: Japanese Patent Application Laid-Open Publication No. 2000-294813